1. Field of the Invention
The present invention generally relates to a cabinet for housing printed circuit boards. More particularly, the present invention relates to an Integrated Modular Avionics (IMA) cabinet for housing printed circuit board modules in avionics systems for airplanes.
2. Description of the Related Art
In general, airplanes contain numerous electronic systems, such as avionics systems, cabin control systems, and energy maintenance systems. The electronic and computer components of these systems are typically disposed on printed circuit boards. In order to protect the printed circuit boards against electromagnetic interference (EMI), radio frequency interference (RFI), environmental contaminants, and vibrations, the printed circuit boards are typically contained in housings which are mounted on shelves in the airplane. Various standards relating to the dimensions and configurations of the printed circuit boards, the housings, and the shelves used in an airplane are described by the ARINC standards, which are generally well known in the art and can be obtained from ARINC Incorporated of Annapolis, Md.
With reference to FIG. 1, a conventional IMA cabinet 100 houses a number of modules 102 containing printed circuit boards. Each module 102 is individually enclosed in a case to protect the printed circuit boards contained within from EMI/RFI. Individually enclosing the modules 102, however, may increase the cost of the modules 102. The conventional IMA cabinet 100 also includes an air plenum 104 for distributing air to the modules 102 to cool the printed circuit boards. The air plenum 104, however, needs to be connected to an air supply, which may be cumbersome and expensive. Additionally, the modules 102 of the conventional IMA cabinet 100 are interconnected to each other and connected to wiring harnesses of the airplane through a circuit interface located at the rear of the conventional IMA cabinet 100. The circuit interface, however, may take up considerable amount of space. For example, in one conventional IMA cabinet, the circuit interface may take up as much as 5 inches out of a total of 20 inches available for the entire cabinet. Additionally, the circuit interfaces are typically difficult to repair or reconfigure.
With reference to FIG. 2, a conventional line replaceable unit (LRU) typically includes a housing 202 for enclosing the printed circuit boards. The LRU 200 also typically includes a motherboard or a bus system for interconnecting the printed circuit boards. Similar to the conventional IMA cabinet 100, however, the conventional LRU 200 is generally difficult to repair and/or reconfigure. In general, the entire LRU 200 is removed to repair or reconfigure the printed circuit boards, which may be costly and time consuming.